Use of a spatial GPS receiver in AMS-02 · PDF fileUse of a spatial GPS receiver in AMS-02...

Use of a spatial GPS receiverin AMS-02 experiment

IPRD06 1-5 October 2006 - SIENA --- Claude Zurbach - LPTA Montpellier

10th Topical Seminar on Innovative Particle and Radiation Detectors

IPRD06Siena 1-5 October 2006

Claude Zurbach

Laboratoire de Physique Théorique et Astroparticules - Montpellier

10th Topical Seminar on Innovative Particle and Radiation Detectors

IPRD06Siena 1-5 October 2006

Claude Zurbach

Laboratoire de Physique Théorique et Astroparticules - Montpellier

Outline

PART 1 : The Alpha Magnetic Spectrometer (AMS-02)

PART 2 : Why to deploy a Global Positioning System receiver in AMS ?

PART 3 : GPS network and GPS receiver : principles and applications

PART 4 : Integration of TOPSTAR 3000D in AMS : expected performances

PART 5 : GPS receiver hardware integration in AMS DAQ system

PART 6 : GPS receiver software integration in AMS DAQ system

PART 7 : Monitoring of the GPS receiver

PART 1 : The Alpha Magnetic Spectrometer (AMS-02)

PART 2 : Why to deploy a Global Positioning System receiver in AMS ?

PART 3 : GPS network and GPS receiver : principles and applications

PART 4 : Integration of TOPSTAR 3000D in AMS : expected performances

PART 5 : GPS receiver hardware integration in AMS DAQ system

PART 6 : GPS receiver software integration in AMS DAQ system

PART 7 : Monitoring of the GPS receiver


3

The Alpha Magnetic Spectrometer : structureThe Alpha Magnetic Spectrometer : structure

On top of AMS, a transition radiation detector tells us the velocities the highest-energy particles

Two (upper and lower) time-of-flight counters tell us lower-energy particles' speeds

The silicon tracker follows a particle's path through the instrument

A superconducting magnet makes the particle's path curve

Underneath AMS, a ring-imaging Cerenkovdetector makes an extremely-accurate velocity measurement for fast particles

Some particles crash violently into the electromagnetic calorimeter, which measures their energy and type

A GPS receiver permits event datation and time synchronization of the detector

A star tracker camera measures AMS's orientation in space

An anti-coincidence veto counter notices stray particles sneaking through AMS sideways

Everything is held up by the unique support structure, served by several racks of custom electronics, and kept cool by a thermal control system


4

Why to deploy a GPS receiver in AMS ?Why to deploy a GPS receiver in AMS ?

The precise determination of time, on the level of the microsecond, is necessary within the framework of the study of the various subjects covered by the experiment:

Galactic Cosmic Rays (GCR) Research of AntimatterDetection of “dark matter”Astrophysic of the Gamma Rays of high energy

Time stamp on events will permit also correlation with others experiments.

The precise determination of time, on the level of the microsecond, is necessary within the framework of the study of the various subjects covered by the experiment:

Galactic Cosmic Rays (GCR) Research of AntimatterDetection of “dark matter”Astrophysic of the Gamma Rays of high energy

Time stamp on events will permit also correlation with others experiments.

The GPS receiver will provide with a precision of a few microseconds

the temporal data (universal time coordinate - UTC) to flag each

detected physical event and for synchronize the internal system of

AMS.

The GPS receiver will provide with a precision of a few microseconds

the temporal data (universal time coordinate - UTC) to flag each

detected physical event and for synchronize the internal system of

AMS.

Various physics subjects and scientific goals in AMS-02 : antimatter, cold dark matter, age of cosmic rays, gamma ray astronomy, primordial black holes, earth’s particle environment, microquasars … and the unknown…


5

GPS network and GPS receiver : principles and applicationsGPS network and GPS receiver : principles and applications

Satellite constellation: 24 satellites arranged in 6 MEO orbital planes with 4 satellites per plane

GPS network of 3 segments: space, control and passive user

Ranging codes and navigation data: broadcast on L1 (1,575.42 MHz) and L2 (1,227.6 MHz)

Time Of Arrival : each satellite transmits on its ranging code which permits to be identified and to determine the transit time and satellite-to-user range

Navigation data : each satellite transmits navigation data which allows the user to determine all the GPS constellation location

PVT determination : three dimensional location requires a TOA ranging measurements from 4 satellites to define Position, Velocity and Time


6

Time, position, velocity an attitude with GPSTime, position, velocity an attitude with GPS

Earth-centered Inertial Coordinate System: ECI coordinate system (axes pointing in fixed directions with respect to the stars), usefull for the GPS satellites to manage their orbital flight

Earth-centered Earth-fixed coordinate System: ECEF coordinate system (x, y, z axes rotage with the earth), more convenient for the GPS receiver to compute height, latitude and longitude positions

World Geodetic System: World Geodetic System 1984 (WGS84) details a model of the earth’s gravitanional irregularities

Satellites transmissions are referenced to highly accurate atomic frequency standards onboard the satellites, synchronized with a GPS System Time managed from the control segment

Universal Time Coordinate: UTC brodcasted by the GPS constellation is derived from atomic clocks (TAI – International Atomic Time) and Earth’s rotation rate; GPS time and UTC time were coincident at 0h January 6, 1980

Earth-centered Inertial Coordinate System: ECI coordinate system (axes pointing in fixed directions with respect to the stars), usefull for the GPS satellites to manage their orbital flight

Earth-centered Earth-fixed coordinate System: ECEF coordinate system (x, y, z axes rotage with the earth), more convenient for the GPS receiver to compute height, latitude and longitude positions

World Geodetic System: World Geodetic System 1984 (WGS84) details a model of the earth’s gravitanional irregularities

Satellites transmissions are referenced to highly accurate atomic frequency standards onboard the satellites, synchronized with a GPS System Time managed from the control segment

Universal Time Coordinate: UTC brodcasted by the GPS constellation is derived from atomic clocks (TAI – International Atomic Time) and Earth’s rotation rate; GPS time and UTC time were coincident at 0h January 6, 1980


7

Integration of TOPSTAR 3000D in AMS : expected performancesIntegration of TOPSTAR 3000D in AMS : expected performances

AMS-02 requirements:

Position accuracy in LEO (Low Earth Orbit) : few m

Time precision accuracy : few µs

Universal Time Coordinate (UTC)

Monitoring degradation C/A (Coarse Acquisition) signal at L1 frequency

AMS-02 requirements:

Position accuracy in LEO (Low Earth Orbit) : few m

Time precision accuracy : few µs

Universal Time Coordinate (UTC)

Monitoring degradation C/A (Coarse Acquisition) signal at L1 frequency

Performances of TOPSTAR 3000D from Alcatel Alenia Space:

Position accuracy in LEO (Low Earth Orbit) : < 10 m

Velocity accuracy in LEO : < 1 cm (/s)

Time accuracy with TCXO (Temperature Controlled Crystal Oscillator) : < 1 µs(AMS02)

TOPSTAR3000D already installed on scientific satellites (Demeter, Swift Gamma-Ray Burst Mission …)

Performances of TOPSTAR 3000D from Alcatel Alenia Space:

Position accuracy in LEO (Low Earth Orbit) : < 10 m

Velocity accuracy in LEO : < 1 cm (/s)

Time accuracy with TCXO (Temperature Controlled Crystal Oscillator) : < 1 µs(AMS02)

TOPSTAR3000D already installed on scientific satellites (Demeter, Swift Gamma-Ray Burst Mission …)


GPS receiver hardware integration in AMSGPS receiver hardware integration in AMS

TOPSTAR functional architecture

RF : radio frequency module (signal reception, analog -> digital, TCXO)

SP : signal processing module (visibility, satellites tracking…)

LOC : localisation module (Diogene navigator : accurate localisation)

RS422 serial output : PPS, teledata (TM) and telecommands (TC)

TOPSTAR functional architecture

RF : radio frequency module (signal reception, analog -> digital, TCXO)

SP : signal processing module (visibility, satellites tracking…)

LOC : localisation module (Diogene navigator : accurate localisation)

RS422 serial output : PPS, teledata (TM) and telecommands (TC)

RS422Antenna

8IPRD06 1-5 October 2006 - SIENA --- Claude Zurbach - LPTA Montpellier

GPS receiver hardware integration in AMSGPS receiver hardware integration in AMS

GPS integration in DAQGPS integration in DAQ

SimPLEX

With antenna simulator

PPS

Data - UTC

GPSE

Power supply 6.3 V &5.2 V USCM

GPS monitoringTMJMDC

Can Bus

GPSJLV1 Trigger system

STR4500

Simplex-Str4500 ™: Hardware and software for orbital flight simulationGPS receiver : TopStar 300D Alcatel AleniaPPS : Pulse Per SecondGPSE : GPS ElectronicsUSCM : Universal Slow Control ModuleJLV1 : Level-A Trigger processorJMDC : Main Data Computer

Simplex-Str4500 ™: Hardware and software for orbital flight simulationGPS receiver : TopStar 300D Alcatel AleniaPPS : Pulse Per SecondGPSE : GPS ElectronicsUSCM : Universal Slow Control ModuleJLV1 : Level-A Trigger processorJMDC : Main Data Computer

9IPRD06 1-5 October 2006 - SIENA --- Claude Zurbach - LPTA Montpellier

10

GPS receiver software integration in AMSGPS receiver software integration in AMS

Hardware :

STR4500 Spirent ™Communication cable for wireless antennaGPS receiverPC Windows

Software :

SimPLEX software ™Scenario (DEMETER in March & ISS in May 2006)

Objective :

The objective is to manage the receiver under the same conditions as on orbital flight with an ISS scenario loaded on a SPIRENT system.

Hardware :

STR4500 Spirent ™Communication cable for wireless antennaGPS receiverPC Windows

Software :

SimPLEX software ™Scenario (DEMETER in March & ISS in May 2006)

Objective :

The objective is to manage the receiver under the same conditions as on orbital flight with an ISS scenario loaded on a SPIRENT system.

How to produce a simulation of the ISS orbital flight ?

And how to reduce time of UTC acquisition ?

Sending with GPS TC : Date and time, Almanach, Doppler informationTime of synchronization : in cold start > 30 min, with aids < 20 min, GPS satellites : ≥ 4

And how to reduce time of UTC acquisition ?

Sending with GPS TC : Date and time, Almanach, Doppler informationTime of synchronization : in cold start > 30 min, with aids < 20 min, GPS satellites : ≥ 4


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Architecture of RF simulation on ISS orbital flightArchitecture of RF simulation on ISS orbital flight

STR4500

Simplex softwareGPS Topstar 3000

Coaxial cable

GPS RF entry


12


GPS control and monitoring from DAQ

Standard mode

The standard mode is considered as the normal way to activate the GPS; it includes the following steps :

initialization by a WMODE telecommand (TC) exploitation of the PPS for internal synchronizationexploitation of the STIME telemesure (TM) to extract the UTC time stamp for each event

Standard mode

The standard mode is considered as the normal way to activate the GPS; it includes the following steps :

initialization by a WMODE telecommand (TC) exploitation of the PPS for internal synchronizationexploitation of the STIME telemesure (TM) to extract the UTC time stamp for each event

Monitoring mode

The operation of the GPS will be followed in time, with a frequency that remains to be specified. We will need particular information concerning the GPS, the status of its acquisition channels, and the quality of the signal received in the L1 band :

extract the tracking status and raw measurement of channels of acquisitionanalyse PVT (position, velocity and time) computed by the navigation softwareextract a general status of the TOPSTAR 3000 receiverto vigilate L1 signal quality

Monitoring mode

The operation of the GPS will be followed in time, with a frequency that remains to be specified. We will need particular information concerning the GPS, the status of its acquisition channels, and the quality of the signal received in the L1 band :

extract the tracking status and raw measurement of channels of acquisitionanalyse PVT (position, velocity and time) computed by the navigation softwareextract a general status of the TOPSTAR 3000 receiverto vigilate L1 signal quality


13


Standard mode: PPS and UTC Time correlation

A PPS synchronous with the 1-second epoch of the GPS constellation time is sent every second to the AMS DAQ The PPS, via the GPSE card, restarts the internal clock of the trigger systemThis PPS (still via the GPSE card) opens a communication gate to a buffer which gets the TM STIME

Considering that all the checks are made by the main computer, the UTC time correlated with the last PPS is available in buffer.

Standard mode: PPS and UTC Time correlation

A PPS synchronous with the 1-second epoch of the GPS constellation time is sent every second to the AMS DAQ The PPS, via the GPSE card, restarts the internal clock of the trigger systemThis PPS (still via the GPSE card) opens a communication gate to a buffer which gets the TM STIME

Considering that all the checks are made by the main computer, the UTC time correlated with the last PPS is available in buffer.

TOPSTAR 3000 GPS

Restarts internal clock Trigger System if Epoch Gate open

EventChecks of Data and storage of UTC Time

Pulse Per Second

Opens Communication Gate

TM STIME

UTC Time

Internal Time (µs)


14

Monitoring of the GPS receiverMonitoring of the GPS receiver

Second fraction and Figure Of Merit Second fraction and Figure Of Merit vsvs time time –– Scenario DemeterScenario Demeter

No UTC time before 400 secondes (no FS)

Drift SF correlated with FOM

FOM stabilization after 1500 secondes (more satellites in view)

Variation of TFOM depending of internal extrapolation, snapshot or navigator calculation


Summary

GPS Project well advanced in AMS-02 experiment

All items related to the implementation in the detector : DAQ/Trigger and

monitoring under way

To be installed at the end of 2008 on International Space Station

GPS Project well advanced in AMS-02 experiment

All items related to the implementation in the detector : DAQ/Trigger and

monitoring under way

To be installed at the end of 2008 on International Space Station

Thanks for your attention …


Use of a spatial GPS receiver in AMS-02 · PDF fileUse of a spatial GPS receiver in AMS-02...

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